No torque no power

[Jogray]

Recently bought a 2009 36v electric ezgo. Seller replaced one battery before I bought he said while hooking radio back up that he crossed radio wires up and burnt them up. This was right before I purchased it. When I was loading it it would barely pull on trailer. Took home and runs good on level ground but slows and almost any incline and will not go up hills just slows to a stop. Batteries all test at 6.2 except one at 6.1. I have 38v coming off batteries while riding it it drops down to around 30v. When I hooked meter to out side of speed controller it shows around 7v while going up to speed on level ground
When i try to go up hill it is only sending 1.5 to 2.5v to motor. Shouldn’t it be sending more volts to motor while going up hill?

[rockfordpi]

Originally Posted by Jogray

Recently bought a 2009 36v electric ezgo. Seller replaced one battery before I bought he said while hooking radio back up that he crossed radio wires up and burnt them up. This was right before I purchased it. When I was loading it it would barely pull on trailer. Took home and runs good on level ground but slows and almost any incline and will not go up hills just slows to a stop. Batteries all test at 6.2 except one at 6.1. I have 38v coming off batteries while riding it it drops down to around 30v. When I hooked meter to out side of speed controller it shows around 7v while going up to speed on level ground
When i try to go up hill it is only sending 1.5 to 2.5v to motor. Shouldn’t it be sending more volts to motor while going up hill?

Test your full pack voltage (the voltage on the input side of your controller) as you go up a hill. Need to know if the loss coming before or after the controller.

[Jogray]

I tested the batteries under load and they dropped down to about 29 volts under load while going up hill

[Jogray]

Batteries are Trojan made feb 2013

[cgtech]

We actually need you to repeat the test directly at the controller B+ & B- terminals, so we will know what the losses look like at the controller.

[rockfordpi]

Originally Posted by Jogray

Batteries are Trojan made feb 2013

Regardless, it is time for batteries. They are dropping way too low under load and are over 7 years old. That is the first issue you have to fix.

I am not sure why controller output is as low as you reported, I will defer that one to the real experts here. I am guessing that is related to batteries, but I can't say for sure you do not have another issue in addition to batteries.

[mfinnegan]

Originally Posted by Jogray

I tested the batteries under load and they dropped down to about 29 volts under load while going up hill

My 36v pack drops to 17 under full load at the controller... but I also got battery #4 dropping to negative 9 volts so there's that

[Jogray]

Looks like losses are the same at controller in the b+ and b- it dropped to 28v

[rockfordpi]

Originally Posted by mfinnegan

My 36v pack drops to 17 under full load at the controller... but I also got battery #4 dropping to negative 9 volts so there's that

I had a battery reverse polarity like that once. It was a new 6v battery that someone had allowed to completely discharge. When I measured pack voltage, I was getting a very low voltage level, but when I checked individual batteries, they all had around 6v.

Nearly drove me crazy until I noticed one of the batteries was -6v. I seperated that one from the pack and charged individually, put it back in, charged and load tested the pack and it tested upward of 80 minutes.

[mfinnegan]

Rockford: 5 of mine read 6.3 volts. 1 reads 5.6v. Put it under load and it all takes a huge dump LOL. That negative reading blew my mind for a minute. I'm gonna charge it separately and try your way. I do have a new one on order to get me thru the season. Gonna change to 3 12v deep cycles eventually. I care very little about range..